Product license verification in Console (#518)

Operator UI - Provide and store License key
- New License section in Operator UI will allow user to provide the
  license key via input form
- New License section in Operator UI will allow the user to fetch the
  license key using subnet credentials
-  Console backend has to verify provided license is valid -
   https://godoc.org/github.com/minio/minio/pkg/licverifier#example-package
-  Console backend has to store the license key in k8s secrets

Operator UI - Set license to tenant during provisioning
- Check if license key exists in k8s secret during tenant creation
- If License is present attach the license-key jwt to the new console
tenant via an environment variable

Operator UI - Set license for an existing tenant
- Tenant view will display information about the current status of the
  Tenant License
- If Tenant doesn't have a License then Operator-UI will allow to attach
new license by clicking the Add License button
- Console backend will extract the license from the k8s secret and save
the license-key jwt in the tenant console environment variable and
redeploy

restapi/error.go

@@ -32,6 +32,8 @@ var (
 	errInvalidEncryptionAlgorithm         = errors.New("error invalid encryption algorithm")
 	errSSENotConfigured                   = errors.New("error server side encryption configuration was not found")
 	errChangePassword                     = errors.New("unable to update password, please check your current password")
+	errInvalidLicense                     = errors.New("invalid license key")
+	errLicenseNotFound                    = errors.New("license not found")
 )
 
 // prepareError receives an error object and parse it against k8sErrors, returns the right error code paired with a generic error message
@@ -95,6 +97,14 @@ func prepareError(err ...error) *models.Error {
 			errorCode = 403
 			errorMessage = errChangePassword.Error()
 		}
+		if errors.Is(err[0], errLicenseNotFound) {
+			errorCode = 404
+			errorMessage = errLicenseNotFound.Error()
+		}
+		if errors.Is(err[0], errInvalidLicense) {
+			errorCode = 404
+			errorMessage = errInvalidLicense.Error()
+		}
 		if madmin.ToErrorResponse(err[0]).Code == "InvalidAccessKeyId" {
 			errorCode = 401
 			errorMessage = errorGenericInvalidSession.Error()